time_series_data <- student_data %>%
  group_by(year.x, major1) %>%
  summarise(placement_rate = sum(placement) / n())

# Time Series Chart
p=ggplot(time_series_data, aes(x = year.x, y = placement_rate, color = major1)) +
  geom_line() +
  labs(title = "Placement Rate Over Time by Major",
       x = "Year",
       y = "Placement Rate") +
  theme_bw()
ggplotly(p)